Pile shell driving core assembly



May 3, 1966 .1. B. TEMPLETON PILE SHELL DRIVING CORE ASSEMBLY 2 Sheets-Sheet 1 Filed July 19, 1961 INVENTOR w n m w 0 m w p A m n a 4 W .m F

y 1966 J. B. TEMPLETON 3,248,337

PILE SHELL DRIVING CORE ASSEMBLY Filed July 19, 1961 2 Sheets-Sheet 2 4Z2 jfl/y if f 2 4 4 If 62 7O 46 4a I. I i

1 43 70 j 32 4 a4. 70 6/ v 3r -3 52 53 l 6! M 6'2 6? k Fl 9 2 h I 42 16 5/ 70v 5/ ar 5 INVENTOR Fug-3 42 John B. Templeton BY ATTORNEYS United States Patent 3,248,887 PILE SHELL DRIVING CORE ASSEMBLY John B. Templeton, 1000 Singleton Blvd., Dallas, Tex. Filed July 19, 1961, Ser. No. 125,182 12 Claims. (Cl. 6153.72)

This invention relates to means for driving tubular piles or shells into the ground and more particularly to a driving core assembly insertable into a pile or shell and engageable therewith.

An object of this invention is to provide a new and improved expansible driving core assembly which may be installed within a thin walled corrugated pile shell for transmitting the impacts of a pile driving means to the pile shell.

Another object is to provide a new and improved expansible driving core assembly which may be installed within a pile shell and expanded into locking engagement therewith whereby driving impacts delivered to the driving core assembly will effectively drive the pile shell without rupturing or distorting the same.

Still another object is to provide an expansible driving core assembly adapted to be received within a pile shell and which is provided with gripping members which may be expanded radially outwardly of the core into frictional engagement with the inner wall of the pile shell to provide a positive drive between the gripping members and the pile shell whereby impacts applied to one end of the driving core assembly will be transmitted uniformly to the pile shell at predetermined spaced points thereon so as to drive the pile shell into the ground without shattering or bending it.

A still further object is to provide an expansible driving core assembly adapted to be received within a pile shell which is expansible by fluid pressure means into gripping engagement with the pile shell for transmitting the impacts of a pile driving means thereto and which is retractable by release of pressure in the fluid pressure means for disengagement from the shell, the expansion and retraction of the driving core being accomplished without the aid of mechanical linkage means, or the like, which would tend to fail under the stress of repeated impacts delivered to the driving core assembly by a pile driver.

Another object is to provide a new and improved method for successively driving a plurality of pile shells with the use of a driving core assembly wherein after the first pile shell is driven into the ground the driving core assembly need not be raised higher than the height of the next pile to be driven into the ground.

Still another object is to provide a method for successively driving a plurality of pile shells with the use of a driving core assembly wherein after the first shell is driven into the ground, the shell next to be driven is held in position adjacent the upper end of the first shell in substantially coaxial alignment therewith, the driving core assembly is raised from the lower driven shell into the shell thereabove and expanded into gripping engagement therewith, the driving assembly and second pile shell then being free to be lifted and moved to a location where it is desired to drive the shell, thereby eliminating the need for raising the driving core assembly any higher than the height of the pile shell next to be driven when it is held positioned adjacent the upper end of the shell which has been driven into the ground.

Additional objects and advantages of the invention will be readily apparent from the reading of the following description of a device constructed in accordance with the invention, and with reference to the accompanying drawings thereof, wherein:

3,248,887 Patented May 3, 1966 FIGURE 1 is a fragmentary, longitudinal, sectional view of a corrugated metal pile shell and of a mandrel or driving core assembly installed therein and in gripping engagement with the inner corrugated wall of the shell;

FIGURE 2 is a transverse cross-section between the spaced rods 51 of FIGURE 1;

FIGURE 3 is a view similar to FIGURE 2, but showing the driving core assembly in collapsed condition out of gripping engagement with the pile shell;

FIGURE 4 is an elevational view, with a portion broken away, of one of the gripping members of the driving core assembly;

FIGURE 5 is a fragmentary view, partly in section, of the upper end portion of the core mandrel of the driving core assembly showing the expansible pneumatic tubes supported thereon and showing the mounting on the core mandrel of air intake members for inflating the expansible tubes;

FIGURE 6 is an elevational view of the core mandrel of the driving core assembly; and,

FIGURE 7 is a sectional view taken along the line 7-7 of FIGURE 6.

Referring particularly to FIGURE 1 of the drawings, the driving core assembly 10 is shown disposed within a thin wall corrugated metal pile shell 11. The driving core assembly comprises a central tubular mandrel or core 12 which is square in cross section and provided with a shock absorbing and positioning foot assembly 13. The foot assembly is adapted to engage a metal boot plate 14 welded along its peripheral edge across the lower end of the pile shell. The foot assembly comprises a shoe 16 rigidly secured, as by welding, or otherwise, to the lower end of a rod 17. The rod 17 extends slidably through a central aperture in a closure plate 18 which closes the lower end of the tubular mandrel. A coil spring 20, which encircles the rod 17, abuts the shoe 16 at its lower end and engages the plate 18 at its other end to provide a yielding support for the mandrel when it is disposed in the pile shell as shown in FIGURE 1. An external flange 21 at the upper end of the rod 17 is provided thereon for retaining the rod in the lower end of the tubular mandrel and limiting its downward movement relative to the mandrel.

Along each of the sides 31, 32, 33 and 34 of the core or mandrel 12 is mounted a longitudinal pile shell gripping member 40 which extends beyond the ends of the mandrel. Each of the gripping members is in the form of a hollow tubular structure defined by an elongate channel member 41 and an elongate curved member 42. The channel member includes a central planar portion 43 with flaring side walls 44 and 45, the outer edges of which are welded along their length to the inner surface of the curved member.

The gripping members are disposed with their planar portions 43 adjacent and parallel to the adjacent flat sides of the mandrel and are adapted to be moved radially of the mandrel between expanded positions and retracted positions. The exterior surface of each of the curved members of each of the gripping members is provided with a series of longitudinally spaced rod sections or ribs 46 which are curved throughout their length to conform to the exterior curved surface of the gripping member. In addition, the ribs 46 are helically curved to conform to the helical spiral corrugations in the inner wall of the pile shell and are welded in position on the gripping member to provide thread-like engagement thereof with the pile shell corrugations when the gripping member is moved radially to expanded position on the mandrel.

The core mandrel is provided with spaced transverse slots for receiving guide rods 51 on which a pair of opposed gripping members 40 are adapted to be mounted for radial movement relative to the mandrel. The guide rods, which are of equal length, are each individually disposed in one of the transverse slots to extend beyond the side edges of the mandrel. The rods 51 on the sides 31 and 33 of the mandrel are arranged in vertically aligned pairs. Similarly, guide rods 52, also arranged in vertically aligned pairs on the sides 32 and 34, support and guide the movements of the other pair of the opposed gripping members 40 in radial directions of the mandrel. Each pair of the rods 52 is spaced longitudinally along the mandrel from the pairs of rods 51. The planar portion 43 of each of the gripping members 40 has apertures 60 for receiving the guide rods in order to mount the gripping members on the mandrel.

A short tubular guide sleeve 61 is disposed in each of the apertures 60 and is secured to the gripping member, preferably by welding. The guide sleeves, which are disposed perpendicularly to the planar portions 43 of the gripping members, serve to insure that the movement of the gripping members on the guide rods is in a radial direction of the core mandrel and also maintain the gripping members with their planar surface parallel to a side of the mandrel throughout their radial movement on the rods, thus insuring that the ribs 46 on all the gripping members engage in the corrugations of the shell without a tendency for rotation as would occur with an odd number of the gripping members. Each of the guide rods is threaded at its ends for receiving a nut 62. The nuts 62 on each pair of guide rods are adapted to engage the ends of the guide sleeves to limit the radial outward movement of the gripping member relative to the mandrel and to retain the gripping member on the guide rods.

The curved members of the gripping members are also provided with apertures 63 for receiving the guide rods. The apertures 63 are of suflicient size to permit the curved members to pass freely over the nuts 62 without engaging the same as the gripping members move radially inwardly or outward on the guide rods.

A flexible pneumatic hose 70 is disposed between the planar surface of each gripping member and the side of the core mandrel which is adjacent and parallel thereto and is attached to the core mandrel by a valve stem 71. Each valve stem extends through aligned apertures in the hose and one side of an air box or manifold 72 which is formed in the upper end of the core mandrel. The end of the valve stem which extends into the manifold is threaded for receiving a nut 73 for securing the hose to the mandrel. Each of the hoses 70 extends along one side of the mandrel substantially from end to end thereof. The hoses are adapted to be inflated by flow of air thereinto through their valve stems, since the ends of the hoses are closed in any suitable manner, whereby expansion of the hoses causes the gripping members to move radially outwardly from the mandrel.

The air box or manifold 72 is formed in the upper end of the tubular mandrel by upper and lower transverse closure plates 74 and 75, respectively, which extend across the bore of the mandrel and together with the sides of the mandrel define the manifold enclosure. A cylindrical tube 76 is threaded into an accommodating aperture in the upper plate 74 of the air box and is provided with an inlet conduit 77 which extends laterally therefrom through an aperture 77a in the channel member of one of the gripping members and is provided with a hose fitting 78 which is disposed through an aperture 78a in the curved member of the gripping member whereby the conduit 77 may be connected in fluid communication with a fluid pressure supply. The upper end of the tube 76 is closed by a head plate or cap 79. The upper ends of the quadrantal gripping members which extend longitudinally beyond the upper end of the core mandrel are disposed in horizontal alignment with the cap 79 on the tube 76. Thus, the impacts delivered to the follower block 80, which telescopes over the gripping member, by a pile driving hammer are applied simultaneously to the four gripping members.

It will be noted that the cap 79 at the upper end of the tube 76 also engages the follower block. Thus, any force applied to the follower block will drive the gripping members downwardly and will drive the mandrel 12 downwardly simultaneously therewith, thereby preventing a shearing action on the guide rod bolts 51 and 52 which otherwise might occur if the gripping members moved longitudinally a greater distance relative to the mandrel than the clearance between the guide bolts and the guide sleeves 61 and between the retainer nuts and the apertures 63. The foot assembly 13 supports the mandrel with the cap 79 thereof flush against the follower block 80 to prevent an upward movement or reaction of the mandrel relative to the gripping members when a driving force is delivered to the follower block. In addition, the foot assembly cushions the downward movement of the mandrel as imparted thereto by the impacts of the driving means On the follower block.

The ribs of the gripping members are adapted to engage the inner wall of the pile shell throughout their longitudinal extent. It will therefore be apparent that when the driving core assembly is disposed within the pile shell with the gripping members in expanded gripping engagement therewith, the repeated application of impacts from a pile driving hammer to the upper end of the driving core assembly will be transmitted uniformly to the pile shell throughout its length. After the piling has been driven to the desired depth, the gripping members are freed for movement toward retracted positions by the release of air pressure from within the pneumatic tubes or hoses.

The follower block 80 atop the mandrel assembly may then be removed and the head plate or cap 79 of the mandrel attached to a hoisting cable, or the like, of a suitable hoisting means. The aperture 77a in the gripping member which receives the inlet conduit 77 is of sufficient dimension to permit lifting of the mandrel sufliciently for the guide rods to act on the gripping members of the mandrel assembly and thereby cause the gripping members of the assembly to retract thereon in response to the camming action of the pile shell corrugations on the helical ribs, whereby the mandrel assembly is disengaged from the pile shell and lifting of the mandrel assembly for extraction from the pile shell will be permitted.

It will therefore be seen that an expansible driving core or mandrel assembly has been disclosed herein which is expansible by fluid pressure means to frictionally engage the inner walls of a pile shell for transmitting the impacts of a pile driving means thereto and which is disengageable from the shell by release of fluid pressure in the fluid pressure means, the expansion and retraction of the driving core being accomplished without the aid of mechanical linkage means, or the like, which generally tend to break under the stress of repeated impacts delivered to a driving core by a pile driver. Although the expansible mandrel assembly illustrated is adapted for use with corrugated pile shells which are circular in cross section, it is to be understood, of course, that the apparatus may also be suitable for the sinking of a smooth-walled tube, and may be structurally modified for use with tubes and pile shells of non-circular cross section.

While the pile shell illustrated has corrugations which are helical and the configuration of the ribs of the expander members corresponds to the helical corrugations, it will be apparent that the pile shell may have annular corrugations in which case the ribs would be formed in sections of circles to conform and fit in such annular corrugations.

When it is desired to drive a plurality of pile shells, the first pile shell may be driven in the manner described above. The driving core assembly within the first pile shell is then collapsed by releasing the air pressure from within the pneumatic hoses to free the four gripping members of the mandrel for movement towards retracted or collapsed positions. A pile shell next to be driven is then held positioned above the driving core assembly above the first pile shell just driven and a hoisting line on the pile driving rig or any other suitable lifting means is then dropped through the upper shell and attached to the core head of the driving core assembly. After detaching the air line hose the driving core assembly is then lifted out of the driven pile shell through and into the pile shell which is next to be driven until the lower ends of the four gripping members are disposed in alignment with the lower end of the pile shell next to be driven. A boot plate is then welded across the bottom of the pile shell, whereby the plate closes the shell and provides a support for the mandrel. The air line hose is then reattached to the driving core assembly and the expander members are then expanded into gripping engagement with the inner walls of the second pile shell whereupon the driving core assembly and the second pile shell may then be positioned at a desired location where the second pile shell is to be driven in the manner described above.

After the second pile shell has been driven, a third and subsequent piles may be driven in identical manner. In each instance after a pile shell has been driven, the expander members are freed for movement to retracted position and another pile shell positioned above the piling just driven and in position for the mandrel to be lifted thereinto and expanded into gripping engagement therewith. The subsequent pile shell may then be lifted and moved to a desired location where it may be driven into the earth.

In this method of driving pile shells, the necessity for lifting the driving core assembly a distance above the ground greater than the height of the pile shell next to be driven may be eliminated, which is particularly desirable when driving tall pile shells. The mandrel need be only lifted sufficiently to clear the upper end of the driven pile shell thus obviating the need for extra strong and extra high hoisting equipment and leads, and saving many man hours of work which would otherwise be required in inserting the driving core assembly into subsequent pile shells after its withdrawal from driven pile shells. For relatively short pile shells, of course, the mandrel may he lifted out of the driven shell and inserted into the shell next to be driven by lowering the mandrel through the upper end thereof.

In the driving core assembly described above, an air pressure supply is preferred as the fluid pressure means. A pressure of about 50 to 150 lbs. per square inch within the hoses is generally sufficient.

The foregoing description of the invention is explanatory only, and changes in the details of the method described and construction illustrated may be made by those skilled in the art, within the scope of the appended claims, without departing from the spirit of the invention.

What is claimed and desired to be secured by Letters Patent is:

1. An expansible driving core assembly for driving corrugated pile shells comprising: a mandrel having a plurality of pairs of opposed parallel planar longitudinal sides; a plurality of elongate gripping structures extending longitudinally of the mandrel and arranged about the axis of said mandrel, said gripping structures having a plurality of projecting ribs on their outer surfaces relative to said mandrel; means for mounting each of said elongate gripping structures on said mandrel for radial movement thereon perpendicularly outwardly relative to one of the planar sides of said mandrel; said gripping structures being mounted in pairs opposite each other and movable outwardly in opposite directions radially with respect to said opposed planar surfaces of said mandrel, whereby the said gripping members grip the opposite inner wall surfaces of a pile shell equally on opposite sides of said mandrel; and means disposed between each gripping structure and the adjacent planar surface of the mandrel for moving said gripping structures radially outwardly of said mandrel to an expanded position whereby said gripping structures are adapted to frictionally engage with the inner wall of a pile shell when said expansible core is disposed therein, said gripping structures being adapted to be retracted inwardly toward said mandrel from said expanded position by camming action of the corrugated inner surface of the pile shell on said projecting ribs when said driving core assembly is moved longitudinally relative to said pile shell; said means for mounting said elongate gripping structures on said mandrel permitting relative longitudinal movement between said mandrel and said gripping means, said supper end of said mandrel being disposed in substantially a common plane with the upper ends of said gripping structures; and resilient support means at the lower end of said mandrel adapted to engage a pile shell enclosure at the lower end of the pile shell to bias the upper end of said mandrel into engagement with a driving means for driving said gripping structures whereby downward impact is applied to the mandrel and to the gripping structures simultaneously to prevent damage to the means mounting the gripping structures on the mandrel, said resilient supporting means at the lower end of the mandrel absorbing the downward impact transmitted to the mandrel by said driving means, whereby the pile shell is driven by the force applied to the upper ends of the gripping structures by the driving means.

2. The expansible driving core assembly of claim 1; and a positioning means mounted on the lower end of said mandrel, said positioning assembly including a member extending downwardly of the lower end of said mandrel and mounted on said mandrel for limited longitudinal movement relative thereto and resilient means engaging said mandrel and said member and biasing said longitudinally movable member downwardly relative to said mandrel, said longitudinally movable member being adapted to engage a closure plate at the lower end of a pile shell when the assembly is disposed in a pile shell to yieldably hold said mandrel in an upper position relative to said gripping structures wherein the upper end of said mandrel is substantially coplanar with the upper ends of said gripping structures.

3. An expansible driving core assembly as described in claim 1 in which said means for moving said gripping structures comprises a plurality of inflatable fluid-tight pipes mounted on said mandrel, each of said pipes being disposed between a planar surface of said mandrel and the adjacent one of said gripping structures with the upper end of each of said fluid-tight pipes being connected to the upper end of the mandrel and provided with connecting means for connection to a common source of fluid under pressure whereby said pipes may be inflated to move said gripping structures radially outwardly of said mandrel.

4. The expansible driving core assembly of claim 3; and a shock absorbing and positioning means mounted on the lower end of said mandrel, said positioning assembly including a member extending downwardly of the lower end of said mandrel and mounted on the mandrel for limited longitudinal movement relative thereto, and resilient means biasing said member downwardly relative to said mandrel, said member being adapted to engage a closure plate at the lower end of a pile shell when the assembly is disposed in a pile shell to yieldably hold said mandrel in an upper position relative to said gripping structures wherein the upper end of said mandrel is substantially coplanar with the upper ends of said gripping structures.

5. An expansible driving core assembly for driving corrugated pile shells comprising: a mandrel; a plurality of elongate gripping sectors having external cylindrical sector faces and extending longitudinally of said mandrel and arranged about the mandrel axis; means for mounting said gripping sectors on said mandrel in radially opposed pairs whereby said gripping sectors are adapted to move radially toward and away from said mandrel in opposed pairs; projecting ribs on the exterior surfaces of said gripping sectors; fluid pressure means for moving said gripping sectors radially away from said mandrel whereby said opposed pairs of gripping sectors are adapted to be moved to grippingly engage the inner wall of a corrugated pile shell with said projecting ribs disposed in the corrugations in said inner wall of the pile shell, said means for mounting said gripping sectors on said mandrel also permitting limited longitudinal movement of said gripping sectors relative to said mandrel and holding the upper end of said mandrel in substantially a common plane with the upper ends of said gripping sectors when said mandrel is in an extreme uppermost position relative to said gripping sectors; means carried by said mandrel adapted to engage an end closure closing one end of a pile shell when the driving core assembly is positioned in a pile shell, said positioning means including biasing means resiliently biasing said mandrel upwardly relative to said gripping sections when said positioning means is in engagement with an end closure of a pile shell whereby the upper ends of said mandrel and gripping sectors are simultaneously engageable by a driving means and a downward blow imparted to said gripping sectors by the driving means is also simultaneously imparted to said mandrel, said biasing means absorbing downward forces imparted to said mandrel by the driving means, said gripping sectors being adapted to impart a downward force to a pile shell engaged thereby the move the same longitudinally when the gripping sectors are in gripping engagement with a pile shell, said gripping sectors being adapted to be retracted inwardly toward said mandrel by camming action of the corrugated inner surface of the pile shell on said projecting ribs when said driving core assembly is moved longitudinally relative to said pile shell, said mandrel and said gripping sectors, when said gripping sectors are in retracted position, being adapted to be moved longitudinally upwardly out of one pile shell and longitudinally through an upper pile shell thereabove to a position in which the upper ends of said mandrel and said gripping surface sectors are disposed in a common horizontal plane above the upper end of the upper pile shell.

6. The driving core assembly of claim wherein said fluid pressure means comprises a plurality of inflatable pipes mounted on said mandrel, each of said pipes being disposed between said mandrel and one of said gripping sectors and provided with means for connecting each of said pipes with a common source of fluid pressure provided at the upper end of said mandrel whereby said pipes may be inflated to move said adjacent gripping sector radially away from said mandrel.

guide means on said mandrel projecting on opposite sides thereof perpendicular to said planar sides thereof; second radial guide means provided on each of the sectors, each of said second guide means adapted to cooperate with said first guide means for guiding the sectors in radial movement with respect to the mandrel perpendicularly to the adjacent planar sides thereof while permitting a limited relative longitudinal axial movement of the sectors with respect to the mandrel; expander means between each of the sectors and the adjacent planar side of the mandrel responsive to fluid pressure for moving said individual longitudinal sectors radially outwardly of said mandrel when fluid pressure is applied to said expander means whereby said sectors may be moved into engagement with the inner wall of a pile shell when said driving core assembly is disposed therein; and positioning means carried by said mandrel, said positioning means being engageable with a closure at the lower end of a pile shell when the driving core assembly is positioned in a pile shell, said positioning means including biasing means for resiliently biasing said mandrel upwardly relative to said gripping sectors when said positioning means is in engagement with a closure at the lower end of a pile shell to dispose the upper end of said mandrel in substantially a common plane With the upper ends of said gripping sectors for engagement by a driving means which is adapted to impart a blow simultaneously to the upper end of the mandrel and the gripping sectors, said positioning means cushioning the impact to the mandrel when a driving means imparts a downward blow to the upper end-s of the mandrel and the gripping sectors whereby said gripping sectors are adapted to transmit a downward force to a pile shell to move the same longitudinally therewith.

8. An expansible driving core assembly responsive to driving means for sinking pile shells into the ground, comprising: a mandrel; individual longitudinal gripping sectors arranged around said mandrel and mounted thereon with their upper ends substantially coplanar with the upper end of said mandrel, whereby the upper ends of said sectors and mandrel are adapted to be simultaneously engaged by a driving means; gripping means on said gripping sectors; expander means between each of the sector-s and the mandrel for moving the sectors outwardly parallel to the longitudinal axis of and radially away from said mandrel; first radial guide means on said mandrel; second radial guide means provided on each of the sectors and adapted to cooperate with the first guide means for guiding the sectors radially with respect to the mandrel as they are moved by said expander means, whereby said sectors are adapted to be moved to grippingly engage the inner wall of a pile shell when said driving core assembly is disposed within said pile shell; said guide means permitting relative longitudinal movement between said mandrel and said gripping sectors; and shock absorbing means on the lower end of said mandrel adapted to engage a closure on the lower end of a pile shell when said assembly is disposed within a pile shell for resiliently biasing said mandrel upwardly relative to a pile shell in which it is positioned to position the upper end of the mandrel in a common plane with the upper ends of said gripping sectors whereby said mandrel is engageable by a driving means simultaneously with said gripping sectors to eliminate upward movement of the mandrel relative to the gripping sectors at the time of impact thereof by the driving means, such shock absorbing means also cushioning the impact to said mandrel to limit longitudinal downward movement of said mandrel relative to said gripping sectors when a driving force is simultaneously applied to the upper ends of said sectors and said mandrel when said sectors are in gripping engagement with the inner wall of a pile shell, said driving force being transmitted to the pile shell by said gripping sectors.

9. An expansible driving core assembly responsive to driving means for sinking pile shells into the ground comprising: a mandrel having a substantially square cross sectional configuration providing two pairs of opposed planar longitudinally extending side surfaces; a plurality of longitudinal gripping sectors arranged around said mandrel and having planar inner surfaces and external cylindrical sector outer gripping faces, said gripping sectors being mounted on said mandrel extending longitudinally parallel to the planar side surfaces of said mandrel and with their inner planar surfaces disposed parallel to such planar side surfaces and with their upper ends substantially coplanar with the upper end of said mandrel whereby said mandrel and sectors are substantially adapted to be simultaneously subjected to a driving force from a driving means; first radial guide means on said mandrel projecting from opposite pairs of sides of said mandrel perpendicular to the planar sides thereof; second radial guide means provided on each of the sectors, each cooperating with said first guide means for guiding the sectors in radial movement laterally inwardly and outwardly with respect to the mandrel while permitting a limited relative longitudinal axial movement of the sectors with respect to said mandrel; expander means between the planar surface of each of the sectors and the adjacent planar side surface of the mandrel responsive to fluid pressure for moving said individual longitudinal sectors radially outwardly of said mandrel when fluid pressure is applied to said expander means, whereby said sectors may be moved into engagement with the inner wall of a pile shell when said driving core assembly is disposed therein; and shock absorbing means on the lower end of said mandrel adapted to engage a closure on the lower end of a pile shell when the driving core assembly is disposed within a pile shell for yieldably biasing said mandrel upwardly relative to said gripping sectors to position the upper end thereof in a common plane with the upper ends of said gripping sectors and for resiliently biasing said mandrel longitudinally upwardly relative to said gripping sectors to position the upper end of said mandrel in a position substantially co-planar with the upper ends of said gripping sectors whereby said mandrel is struck simultaneously with said sectors by a driving means to prevent upward longitudinal movement of said mandrel relative to said gripping sectors when so struck an impact and for cushioning the impact to said mandrel to limit downward relative movement of said mandrel with respect to said gripping sectors whereby downward force is transmitted by said gripping sectors to said pile shell when a driving force is simultaneously applied to the upper ends of said sectors and mandrel.

10. An expansible driving core assembly for use in driving a corrugated pile shell comprising: a mandrel; a plurality of opposed pairs of gripping members arranged peripherally about said mandrel, said gripping members each having outer arcuate shaped surfaces; means for mounting said gripping members in opposed pairs on said mandrel for radial lateral movement with respect thereto; expansible and contractible fluid pressure container means mounted between each of said gripping members and said mandrel, said pressure containers when in expanded inflated condition forcing said gripping members radially laterally outwardly of said mandrel to an expanded position wherein their outer arcuate surfaces are adapted to contact the inner surface of a pile shell when said expansible driving core assembly is disposed therein; and a plurality of rod segments secured to each of said outer arcuate shaped surfaces in longitudinally spaced array thereon whereby said rod segments are adapted to frictionally engage the inner wall of said pile shell when said gripping members are in expanded position, said means for mounting said gripping members on said mandrel also permitting limited longitudinal movement of said gripping members relative to said mandrel; positioning means at the lower end of said mandrel adapted to engage a closure at the lower end of a pile shell when said assembly is disposed in a pile shell, said positioning means including means resiliently biasing said mandrel upwardly relative to said gripping members when said assembly is disposed in a pile shell and said positioning means is in engagement with a closure of the pile shell to a position wherein its upper end is substantially coplanar with the upper ends of said gripping members whereby a downward blow imparted to said gripping members by a driving means adapted to engage the upper ends of said mandrel and said gripping members is imparted simultaneously to said mandrel, said resilient means absorbing downward forces imparted to said mandrel by a driving means to limit downward relative movement between said mandrel and said gripping means when a downward force is applied to the upper end of said gripping means and said mandrel, and whereby the downward force applied to said gripping means is transmitted by said gripping means through said rod segments to a pile shell to cause longitudinal movement of the pile shell with said gripping members, said gripping members being retractable from said expanded position by camming action of the corrugated inner surface of said pile shell against said rod segments when said driving core assembly is moved longitudinally relative to said pile shell, said mandrel and said gripping members when retracted being movable longitudinally upwardly through said pile shell and through a pile shell thereabove to a position in which the upper end-s of said mandrel and of said gripping members are disposed above the upper end of said upper pile shell.

11. A driving core assembly for use in driving pile shells including; an elongate mandrel; a plurality of elongate laterally movable gripping means disposed about said mandrel and extending longitudinally relative to said mandrel; means for mounting said gripping means on said mandrel for relative lateral movement with respect to the longitudinal axis of said mandrel and for limited longitudinal movement relative to said mandrel and including coengageable means on said gripping means and said mandrel limiting longitudinal and lateral movement of said gripping means relative to said mandrel; said gripping means being disposed with their upper ends substantially coplanar with the upper end of said mandrel, whereby said mandrel and said gripping means are adapted to be simultaneously subjected to a driving force from a driving means applied to the upper end-s thereof; elongate expansible and contractible fluid pressure expansible expander means engageable with said mandrel and said gripping members for moving said gripping members outwardly of said mandrel from retracted position to projecting position relative to said mandrel; said mandrel having a common fluid pressure chamber formed in the upper end thereof and means providing flow communication between said common fluid pressure chamber and said expander means, whereby fluid pressure introduced into said pressure chamber is directed into said expander means to force the gripping means laterally outwardly to expanded position; resilient positioning and supporting means mounted on the lower end of said mandrel and extending below the lower ends of said gripping means and adapted to engage a closure means at the lower end of a pile shell when said driving core assembly is disposed in a pile shell to yieldably bias said mandrel upwardly to an upper position relative to said gripping means in which the upper ends of said gripping means and said mandrel are disposed substantially coplanar, whereby the downward force is applied to the upper ends of the gripping means and the mandrel simultaneously to limit upward longitudinal movement of the mandrel relative to the gripping means when the blow is struck, said resilient supporting means permitting limited longitudinal downward movement of the mandrel relative to the gripping means after the blow is struck.

12. The driving core assembly of claim 11 wherein said positioning and supporting means includes: an elongate member longitudinally slidably mounted in the lower end of the mandrel and having a supporting surface at its lower end extending below the lower ends of said grippings means; and resilient means engageable vw'th said mandrel and said elongate member biasing said member downwardly relative to said mandrel for biasing said mandrel upwardly relative to said gripping means to dispose the upper end of the mandrel in substantially coplanar alignment with the upper end of the gripping means when said driving core assembly is disposed within 1 1 1 2 a pile shell with the supporting surface in engagement 2,990,688 7/ 1961 Cobi 61-53.72 with a closure means at the lower end of a pile shell. 3,006,151 10/ 1961 lourdain 61-53.72 3,006,152 10/1961 Rusehe 61--53.72

References Cited by the Exeminer UNI-TED STATES PATENTS FOREIGN TENTS 1,912,108 5/1933 Upson 61'--53.7 7,454 5/ 1909 Great Britain- 3 I V M 2 ig zggg 3;}; GHARLES E.YOCONNELL, Primary Examiner. 2,869,329 1/1959 Tourdain 61-5312 WILLIAM I. BUSHAKE, EARL J. WITMER,

2,881,592 4/1959 Cobi 61'53.72 10 Examiners. 

1. AN EXPANSIBLE DRIVING CORE ASSEMBLY FOR DRIVING CORRUGATED PILE SHELLS COMPRISING: A MANDREL HAVING A PLURALITY OF PAIRS OF OPPOSED PARALLEL PLANAR LONGITUDINAL SIDES; A PLURALITY OF ELONGATE GRIPPING STRUCTURES EXTENDING LONGITUDINALLY OF THE MANDREL AND ARRANGED ABOUT THE AXIS OF SAID MANDREL, SAID GRIPPING STRUCTURES HAVING A PLURALITY OF PROJECTING RIBS ON THEIR OUTER SURFACES RELATIVE TO SAID MANDREL; MEANS FOR MOUNTING EACH OF SAID ELONGATE GRIPPING STRUCTURES ON SAID MANDERL FOR RADIAL MOVEMENT THEREON PERPENDICULARLY OUTWARDLY RELATIVE TO ONE OF THE PLANAR SIDES OF SAID MANDREL; SAID GRIPPING STRUCTURES BEING MOUNTED IN PAIRS OPPOSITE EACH OTHER AND MOVABLE OUTWARDLY IN OPPOSITE DIRECTIONS RADIALLY WITH RESPECT TO SAID OPPOSED PLANAR SURFACES OF SAID MANDREL, WHEREBY THE SAID GRIPPING MEMBERS GRIP THE OPPOSITE INNER WALL SURFACES OF A PILE SHELL EQUALLY ON OPPOSITE SIDES OF SAID MANDREL; AND MEANS DISPOSED BETWEEN EACH GRIPPING STRUCTURE AND THE ADJACENT PLANAR SURFACE OF THE MANDREL FOR MOVING SAID GRIPPING STRUCTURES RADIALLY OUTWARDLY OF SAID MANDREL TO AN EXPANDED POSITION WHEREBY SAID GRIPPING STRUCTURES ARE ADAPTED TO FRICTIONALLY ENGAGE WITH THE INNER WALL OF A PILE SHELL WHEN SAID EXPANSIBLE CORE IS DISPOSED THEREIN, SAID GRIPPING STRUCTURES BEING ADAPTED TO BE RETRACTED INWARDLY TOWARD SAID MANDREL FROM SAID EXPANDED POSITION BY CAMMING ACTION OF THE CORRUGATED INNER SURFACE OF THE PILE SHELL ON SAID PROJECTING RIBS WHEN SAID DRIVING CORE ASSEMBLY IN MOVED LONGITUDINALLY RELATIVE TO SAID PILE SHELL; SAID MEANS FOR MOUNTING SAID ELONGATE GRIPPING STRUCTURES ON SAID MANDREL PERMITTING RELATIVE LONGITUDINAL MOVEMENT BETWEEN SAID MANDREL AND SAID GRIPPING MEANS, SAID SUPPER END OF SAID MANDREL BEING DISPOSED IN SUBSTANTIALLY A COMMON PLANE WITH THE 